arm64: dts: ti: k3-am642-evm: Do not split single items

Each "mboxes" item is composed of two cells. It seems these got split
as they appeared to be two items in an array, but are actually a single
two-cell item. Rejoin these cells.
Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20240123222536.875797-1-afd@ti.comSigned-off-by: Vignesh Raghavendra <vigneshr@ti.com>

arch/arm64/boot/dts/ti/k3-am642-evm.dts

@@ -660,25 +660,25 @@ mbox_m4_0: mbox-m4-0 {
 };
 
 &main_r5fss0_core0 {
-	mboxes = <&mailbox0_cluster2>, <&mbox_main_r5fss0_core0>;
+	mboxes = <&mailbox0_cluster2 &mbox_main_r5fss0_core0>;
 	memory-region = <&main_r5fss0_core0_dma_memory_region>,
 			<&main_r5fss0_core0_memory_region>;
 };
 
 &main_r5fss0_core1 {
-	mboxes = <&mailbox0_cluster2>, <&mbox_main_r5fss0_core1>;
+	mboxes = <&mailbox0_cluster2 &mbox_main_r5fss0_core1>;
 	memory-region = <&main_r5fss0_core1_dma_memory_region>,
 			<&main_r5fss0_core1_memory_region>;
 };
 
 &main_r5fss1_core0 {
-	mboxes = <&mailbox0_cluster4>, <&mbox_main_r5fss1_core0>;
+	mboxes = <&mailbox0_cluster4 &mbox_main_r5fss1_core0>;
 	memory-region = <&main_r5fss1_core0_dma_memory_region>,
 			<&main_r5fss1_core0_memory_region>;
 };
 
 &main_r5fss1_core1 {
-	mboxes = <&mailbox0_cluster4>, <&mbox_main_r5fss1_core1>;
+	mboxes = <&mailbox0_cluster4 &mbox_main_r5fss1_core1>;
 	memory-region = <&main_r5fss1_core1_dma_memory_region>,
 			<&main_r5fss1_core1_memory_region>;
 };